Auxiliary storage pools

An auxiliary storage pool (ASP) is one or more physical disk units assigned to the same storage area. ASPs allow you to isolate certain types of objects on specified physical disk units.

The system ASP isolates system programs and the temporary objects that are created as a result of processing by system programs. User ASPs can be used to isolate some objects such as libraries, SQL objects, journals, journal receivers, applications, and data. The IBM® i product supports up to 32 basic user ASPs, and 223 independent user ASPs. Isolating libraries or objects in a user ASP protects them from disk failures in other ASPs and reduces recovery time.

In addition to reduced recovery time and isolation of objects, placing objects in an ASP can improve performance. If a journal receiver is isolated in a user ASP, the disks associated with that ASP are dedicated to that receiver. In an environment that requires many read and write operations to the database files, this can reduce arm contention on the disks in that ASP, and can improve journaling performance.